GNS Science

Revised descriptions of New Zealand Cenozoic Mollusca from Beu and Maxwell (1990)

New Zealand Cenozoic Mollusca

Zeacuminia tahuia Finlay, 1930


(Pl. 8y): GS9508, J40/f8803, McCulloch's Bridge, Kaiatan (GNS)

Beu & Maxwell (1990): Chapter 8; p. 124; pl. 8 y.

Synonymy: Terebra sulcata Marshall 1919, p. 232 (not Terebra swainsoni var. sulcata Pease, 1868); Zeacuminia tahuia Finlay 1930a, p. 47 (new name for Terebra sulcata Marshall, preoccupied)

Type species of Zeacuminia Finlay, 1930

Classification: Terebridae

Description: Size moderate for genus (height 20-32 mm), spire elevated. Protoconch conical, of about 5 strongly convex whorls, last whorl with a fine suprasutural thread and narrow, arcuate costellae, remainder smooth. Teleoconch of up to 13 weakly to moderately convex whorls, most specimens with a broad, shallow sulcus adapically; last whorl contracted rapidly with a short, twisted neck. Axial sculpture of narrow, sharp-crested opisthocyrt costae with broad concave interspaces, reaching from suture to suture on spire but dying out on periphery or upper part of base of last whorl; 13-17 on penultimate whorl. Spiral sculpture of very fine grooves and threads, usually absent because of abrasion. Aperture small, ovate; columella twisted to left at inception of short, shallowly notched siphonal canal. Inner lip impressed, outer lip thin, concave. Fasciole prominent, ridge-margined.

Comparison: Zeacuminia tahuia is distinguished from other New Zealand terebrids by its slender shape, its narrow, sharp-crested axial costae and its very weak spiral sculpture. Z. tahuia is the earliest known species of Zeacuminia, a genus to which most New Zealand terebrids have been assigned, even though it is not clear just how it differs from other axially costate members of the family. The genus as a whole seems to have been bathymetrically tolerant, with some species living in very shallow waters and others in outer shelf or upper bathyal habitats. The generic classification of the larger New Zealand terebrids (i.e., other than Pervicacia and Kaweka species) requires reassessment.

Distribution: Bortonian-Kaiatan; Bortonian, Hampden Formation, Hampden Beach (type) (rare); Waihao Greensand, McCulloch's Bridge (common); Kapua Tuff, Waihao River (rare).

Cite this publication as: "A.G. Beu and J.I. Raine (2009). Revised descriptions of New Zealand Cenozoic Mollusca from Beu and Maxwell (1990). GNS Science miscellaneous series no. 27."
© GNS Science, 2009
ISBN 978-0-478-19705-1
ISSN 1177-2441
(Included with a PDF facsimile file copy of New Zealand Geological Survey Paleontological Bulletin 58 in CD version from: Publications Officer, GNS Science, P.O. Box 30368 Lower Hutt, New Zealand)


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